VirtualBox

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Manual: known limitations

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1<?xml version="1.0" encoding="UTF-8"?>
2<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
3"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
4<chapter id="KnownIssues">
5 <title>Known limitations</title>
6
7 <para>This sections describes known problems with VirtualBox
8 $VBOX_VERSION_STRING. Unless marked otherwise, these issues are planned to
9 be fixed in later releases.</para>
10
11 <itemizedlist>
12 <listitem>
13 <para>The following <emphasis role="bold">Guest SMP (multiprocessor)
14 limitations</emphasis> exist:<itemizedlist>
15 <listitem>
16 <para><emphasis role="bold">Poor performance</emphasis> with
17 32-bit guests on AMD CPUs. This affects mainly Windows and Solaris
18 guests, but possibly also some Linux kernel revisions. Partially
19 solved in 3.0.6 for 32 bits Windows NT, 2000, XP and 2003 guests.
20 Requires 3.0.6 or higher Guest Additions to be installed.</para>
21 </listitem>
22
23 <listitem>
24 <para><emphasis role="bold">Poor performance</emphasis> with
25 32-bit guests on certain Intel CPU models that do not include
26 virtual APIC hardware optimization support. This affects mainly
27 Windows and Solaris guests, but possibly also some Linux kernel
28 revisions. Partially solved in 3.0.12 for 32 bits Windows NT,
29 2000, XP and 2003 guests. Requires 3.0.12 or higher Guest
30 Additions to be installed.</para>
31 </listitem>
32 </itemizedlist></para>
33 </listitem>
34
35 <listitem>
36 <para><emphasis role="bold">64-bit guests on some 32-bit host systems
37 with VT-x</emphasis> can cause instabilities to your system. If you
38 experience this, do not attempt to execute 64-bit guests. Refer to the
39 VirtualBox user forum for additional information.</para>
40 </listitem>
41
42 <listitem>
43 <para>For <emphasis role="bold">Direct3D support in Windows
44 guests</emphasis> to work, the Guest Additions must be installed in
45 Windows "safe mode". Press F8 when the Windows guest is booting and
46 select "Safe mode", then install the Guest Additions. Otherwise Windows'
47 file protection mechanism will interfere with the replacement DLLs
48 installed by VirtualBox and keep restoring the original Windows system
49 DLLs.</para>
50 </listitem>
51
52 <listitem>
53 <para><emphasis role="bold">Guest control.</emphasis> On Windows guests,
54 a process lauched via the guest control execute support will not be able
55 to display a graphical user interface <emphasis>unless</emphasis> the
56 user account under which it is running is currently logged in and has a
57 desktop session.</para>
58
59 <para>Also, to use accounts without or with an empty password, the
60 guest's group policy must be changed. To do so, open the group policy
61 editor on the command line by typing
62 <computeroutput>gpedit.msc</computeroutput>, open the key
63 <emphasis>Computer Configuration\Windows Settings\Security
64 Settings\Local Policies\Security Options</emphasis> and change the value
65 of <emphasis>Accounts: Limit local account use of blank passwords to
66 console logon only</emphasis> to <emphasis>Disabled</emphasis>.</para>
67 </listitem>
68
69 <listitem>
70 <para><emphasis role="bold">Compacting virtual disk images is limited to
71 VDI files.</emphasis> The <code>VBoxManage modifyhd --compact</code>
72 command is currently only implemented for VDI files. At the moment the
73 only way to optimize the size of a virtual disk images in other formats
74 (VMDK, VHD) is to clone the image and then use the cloned image in the
75 VM configuration.</para>
76 </listitem>
77
78 <listitem>
79 <para><emphasis role="bold">OVF import/export:</emphasis><itemizedlist>
80 <listitem>
81 <para>OVF localization (multiple languages in one OVF file) is not
82 yet supported.</para>
83 </listitem>
84
85 <listitem>
86 <para>Some OVF sections like StartupSection,
87 DeploymentOptionSection and InstallSection are ignored.</para>
88 </listitem>
89
90 <listitem>
91 <para>OVF environment documents, including their property sections
92 and appliance configuration with ISO images, are not yet
93 supported.</para>
94 </listitem>
95
96 <listitem>
97 <para>Remote files via HTTP or other mechanisms are not yet
98 supported.</para>
99 </listitem>
100 </itemizedlist></para>
101 </listitem>
102
103 <listitem>
104 <para>Neither <emphasis role="bold">scale mode</emphasis> nor <emphasis
105 role="bold">seamless mode</emphasis> work correctly with guests using
106 OpenGL 3D features (such as with compiz-enabled window managers).</para>
107 </listitem>
108
109 <listitem>
110 <para>On <emphasis role="bold">Mac OS X hosts,</emphasis> the following
111 features are not yet implemented: </para>
112
113 <para><itemizedlist>
114 <listitem>
115 <para>Numlock emulation</para>
116 </listitem>
117
118 <listitem>
119 <para>CPU frequency metric</para>
120 </listitem>
121
122 <listitem>
123 <para>Memory ballooning</para>
124 </listitem>
125 </itemizedlist></para>
126 </listitem>
127
128 <listitem>
129 <para><emphasis role="bold">Mac OS X Server guests:</emphasis>
130 <itemizedlist>
131 <listitem>
132 <para>Mac OS X Server guests can only run on a certain host
133 hardware. For details about license and host hardware limitations,
134 please see <xref linkend="intro-macosxguests" />.</para>
135 </listitem>
136
137 <listitem>
138 <para>VirtualBox does not provide Guest Additions for Mac OS X
139 Server at this time.</para>
140 </listitem>
141
142 <listitem>
143 <para>The graphics resolution currently defaults to 1024x768 as
144 Mac OS X Server falls back to the built-in EFI display support.
145 See <xref linkend="efividmode" /> for more information on how to
146 change EFI video modes.</para>
147 </listitem>
148
149 <listitem>
150 <para>Even when idle, Mac OS X Server guests currently burn 100%
151 CPU. This is a power management issue that will be addressed in a
152 future release.</para>
153 </listitem>
154
155 <listitem>
156 <para>Mac OS X Server guests only work with one CPU assigned to
157 the VM. Support for SMP will be provided in a future
158 release.</para>
159 </listitem>
160
161 <listitem>
162 <para>Depending on your system and version of Mac OS X Server, you
163 might experience guest hangs after some time. This can be fixed by
164 turning off energy saving (set timeout to "Never") in the system
165 preferences.</para>
166 </listitem>
167
168 <listitem>
169 <para>By default, the VirtualBox EFI enables debug output of the
170 Mac OS X Server kernel to help you diagnose boot problems. Note
171 that there is a lot of output and not all errors are fatal (they
172 would also show on your physical Mac). You can turn off these
173 messages by issuing this command:<screen>VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" " "</screen>To
174 revert to the previous behavior, use:<screen>VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" ""</screen></para>
175 </listitem>
176 </itemizedlist></para>
177 </listitem>
178
179 <listitem>
180 <para><emphasis role="bold">Solaris hosts:</emphasis> <itemizedlist>
181 <listitem>
182 <para>There is no support for USB devices connected to Solaris 10
183 hosts.</para>
184 </listitem>
185
186 <listitem>
187 <para>USB support on Solaris hosts requires kernel version snv_124
188 or higher. Webcams and other isochronous devices are known to have
189 poor performance.</para>
190 </listitem>
191
192 <listitem>
193 <para>No ACPI information (battery status, power source) is
194 reported to the guest.</para>
195 </listitem>
196
197 <listitem>
198 <para>No support for using wireless adapters with bridged
199 networking.</para>
200 </listitem>
201 </itemizedlist></para>
202 </listitem>
203
204 <listitem>
205 <para><emphasis role="bold">Guest Additions for OS/2.</emphasis> Shared
206 folders are not yet supported with OS/2 guests. In addition, seamless
207 windows and automatic guest resizing will probably never be implemented
208 due to inherent limitations of the OS/2 graphics system.</para>
209 </listitem>
210 </itemizedlist>
211</chapter>
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